bpo-39573: Add Py_IS_TYPE() function (GH-18488)

Co-Author: Neil Schemenauer <nas-github@arctrix.com>
diff --git a/Include/code.h b/Include/code.h
index 3afddd2..107eba4 100644
--- a/Include/code.h
+++ b/Include/code.h
@@ -115,7 +115,7 @@
 
 PyAPI_DATA(PyTypeObject) PyCode_Type;
 
-#define PyCode_Check(op) (Py_TYPE(op) == &PyCode_Type)
+#define PyCode_Check(op) Py_IS_TYPE(op, &PyCode_Type)
 #define PyCode_GetNumFree(op) (PyTuple_GET_SIZE((op)->co_freevars))
 
 /* Public interface */